The three connected lakes — Qianhai, Houhai, and Xihai — that form the Shichahai area in the northwest of the old city were once the terminus of the Grand Canal and the water supply for the imperial city. The surrounding neighbourhood of willow-lined banks, historic mansions, and narrow hutong lanes is one of the most atmospheric parts of central Beijing. In summer, the lake shores fill with restaurants, bars, and boating; in winter the lakes freeze and become an ice-skating rink.
The bar street along the south shore of Houhai is lively but touristy — better to walk north around the quieter shores where local teahouses and a handful of decent restaurants are mixed in with historic residences. Prince Gong's Mansion, the best-preserved Qing-era aristocratic compound in Beijing, is nearby. Hire a bicycle and cycle the perimeter of all three lakes for the best overview of the area.